Translation of abstract (English)

Artificial molecular electron donor / electron acceptor systems are key compounds for the elucidation of mechanistic details of photoinduced electron transfer processes (PET processes) in chemistry and biology. They are fundamental for the design of future artificial photosystems and they might find application in molecular optoelectronic devices or sensors. In this thesis the selective synthesis of trans-AB2C-substituted meso-tetraaryl porphyrins are reported. These porphyrins should be selectively functionalized with the electron donor ferrocene either at the A-site or the C-site. The meso-tetraaryl porphyrin synthesis has been optimized for the combination A = C6H4-NO2, B = C6H5 and C = C6H4COOMe using the respective substituted dipyrromethanes (A = C6H4-NO2, C = C6H4COOMe). The nitro group of this porphyrin is reduced by tin(II) chloride to the amine and the ester of this porphyrin is hydrolyzed to the carboxylic acid under alkaline conditions. As the reaction sequence is arbitrary the trans-AB2C-substituited porphyrin with A = C6H4-NH2 / C = C6H4COOMe, A = C6H4-NO2 / C = C6H4COOH und A = C6H4-NH2 / C = C6H4COOH are obtained in good yields. Metallation of these porphyrins with zinc(II) or copper(II) is also successful in good yields. The functional groups of the free base porphyrins (A = C6H4-NH2 / C = C6H4COOH) can be selectively conjugated to ferrocene building blocks (ferrocene carboxylic acid or amino ferrocene) via amide bonds whereupon activation of the carboxylic acid is accomplished by hydroxy benzotriazole or by using acid chlorides. The amide coupling reactions result in ferrocene-porphyrin dyads with the following substitution patterns: A = C6H4-NH-CO-Fc / C = C6H4COOMe, A = C6H4-NO2 / C = C6H4CO-NH-Fc, A = C6H4-NHFmoc / C = C6H4CO-NH-Fc and A = C6H4-NH2 / C = C6H4CO-NH-Fc. In these dyads the fluorescence of the porphyrin chromophore is partially quenched which results from intramolecular photoinduced electron transfer processes from the ferrocene donor to the excited porphyrin. The efficiency of the PET in these amide-linked dyads depends on the redox potential of the attached ferrocene and the surrounding medium (solvent).